摘要:

AbstractThe crystal growth rate under diffusion control is considered. Together with nutrient diffusion, the physi‐sorption of an inert gas, which impedes the surface kinetics during vapour growth, is taken into consideration. In this way the size of the diffusion field surrounding vapour grown crystals was estimated. The relations obtained are checked with data for the growth of zinc single crystals in argon atmosphere. The appearance of shallow cavities on their basal faces is used as a morphological mark for growth under diffusion control. Besides, the microstructure of the inner edge of the macroscopically flat periphery, surrounding the shallow cavities is investigated experimentally, by means of SE

ISSN:0232-1300    

DOI:10.1002/crat.2170320502

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170320503

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe influence of tartaric acid (TA) on both the growth kinetics and morphology of silver single crystals was investigated insituduring electrocrystallization. Using laser interferometry the dependence of the monoatomic step velocity vs. overvoltage at different concentrations of TA was studied. Measuring the normal growth rateRwe calculated the current on the front crystal face. It is shown that the addition of TA changes its value in complicated way vs. overvoltage.

ISSN:0232-1300    

DOI:10.1002/crat.2170320504

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractHen‐egg‐white lysozyme (HEWL) crystals does not differ from small molecule crystals in respect to diffusion limited growth but differ substantially as far as lattice bound strength is concer

ISSN:0232-1300    

DOI:10.1002/crat.2170320505

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170320506

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractMorphologic and kinetic behaviour of the hill of the (001) face of TGS crystal, generated by unparallel dislocation center of growth under inconstant supersaturation and temperature has been experimentally examined. Some irreversible changes in the shape of the hill top, as a hysteresis in its normal rate of growth is registered. A model, on the base of which a qualitative anylsis of the phenomenon is proposed.

ISSN:0232-1300    

DOI:10.1002/crat.2170320507

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe hydrothermal treatment of different glasses of the composition 2 Na2O–8 CaO–10 Al2O3– 20 SiO2and 2 BaO–2 Al2O3–6 SiO2at one kilobar pressure in a temperature‐range between 80 °C and 230 °C lead to the formation of the zeolite‐minerals thomsonite (orthorhombic symmetry space‐group Pbmn,a= 13.05 Å,b= 13.09 Å andc= 13.22 Å), and edingtonite (orthorhombic symmetry, space‐group: P2,2,2,a= 9.55 Å,b= 9.67 Å andc= 6.52 Å). Under the chosen hydrothermal conditions both mineral phases are formed in the w

ISSN:0232-1300    

DOI:10.1002/crat.2170320508

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe morphological features of ZnO crystallites influenced by solution basicity under hydrothermal conditions have been studied from the standpoint of the incorporation of the growth units. A crystal chemistry approach is developed to understand and thus to control a desirable morphology of the crystallites. The effects of the additive OH−on the crystal morphology of ZnO crystallites are qualitatively but satisfactorily explained by a mechanism considering two aspects: (1) solution structures and the structural forms of growth units under a certain growth condition, i.e. the interactions between the solvent molecules and the growth units; and (2) the influence of the solvent molecules or additives on growth interfaces, particularly on two polar faces of ZnO crystallites in terms of the inhibition or promotion of the incorporation of various growth units depending on the solution basicity. Since the incorporation rates of the growth units are different on positive and negative polar faces, the relative growth rates of these faces are different and thus lead to the habit modifications. The approach clearly demonstrates that the hindrance of crystal growth is a consequence of surface adsorption processe

ISSN:0232-1300    

DOI:10.1002/crat.2170320509

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractTemperature induced surface transitions in liquid crystal hybrid cells with asymmetrical anchoring, planar to one surface and tilted to the other, are experimentally studied. The results are theoretically explained by an elastic theory and the resulting values for the effective splay‐bend elastic constant for a given liquid crystal, as well as the parameters characterising the anchoring on the boundary surface with tilted anchoring are compared with data from previous experiments, with good agreemen

ISSN:0232-1300    

DOI:10.1002/crat.2170320510

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY

摘要:

AbstractThe present paper reports the theory of crystalloluminescence (CRL) produced during the micro‐fracture of growing crystallites. Surface charges may be developed during the micre‐fracture of crystallites due to several processes like piezoelectrification, movement of charged dislocations, barodiffusion of defects near the moving crack etc. The surface charges may be neutralized by the movement of charge carriers produced due to the dielectric breakdown near the surface of crystallites and consequently the recombination luminescence may occur. Considering the basic concepts of crystallization from the supersaturated solution, expressions are derived which are able to explain satisfactorily the temporal, thermal, spectral concentration and other characteristics of the CRL. It is shown that the induction period for crystal nucleation, lifetime of supersaturation, size of crystallites and time constant for the relaxation of charges on the newly created surfaces may be determined from the CRL measureme

ISSN:0232-1300    

DOI:10.1002/crat.2170320511

出版商:WILEY‐VCH Verlag    

年代:1997

数据来源: WILEY